University of Architecture, Civil Engineering and Geodesy

About: University of Architecture, Civil Engineering and Geodesy is a education organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Finite element method & Beam (structure). The organization has 3808 authors who have published 3822 publications receiving 30736 citations. The organization is also known as: Sofia Polytechnic.

Mathematical Modeling and Experimental Studies of the Joint Electrodeposition of Gold and Silver from Sulfuric Acid Thiourea Solutions on Flow-Through 3D Electrode Taking into Account Its Nonstationary State

Abstract: Mathematical models of electrochemical processes in reactors with flow-through 3D electrodes for the electrodeposition of metals from a polycomponent electrolyte solution have been presented The parameters of the process and electrode, such as the flow rate of the electrolyte, porosity, specific surface, and the specific conductivity of the electrode and solution, at each electrode point during electrolysis have been taken into account The mathematical models and methods for determining the electrochemical and hydrodynamic parameters of multicomponent electrochemical systems have been described The data have been used to calculate industrial electrochemical processes in flow-through 3D electrodes The adequacy of these methods has been shown The experimental and calculated data on the electrodeposition of gold and silver from sulfuric acid thiourea solutions to carbon-graphite fiber cathodes have been analyzed The dependences of electrodeposition parameters on the electrolysis conditions, the initial properties of the electrode-solution system, and the concentration ratio of gold and silver in the solution taking into account the joint reduction of hydrogen ions and molecular oxygen have been examined The current and resulting regularities of the processes have been revealed The adequacy of the mathematical models for industrial joint electrodeposition of gold and silver from sulfuric acid thiourea solutions on flow-through 3D electrodes taking into account the side electrode reactions has been shown The appearance of anode zones on a cathode polarized carbon fiber flow electrode during the deposition of metals from multicomponent systems has been considered

Effect of Orientation of the Solar Wind Magnetic Clouds on the Seasonal Variation of Geomagnetic Activity

Abstract: An analysis is made of the causes of seasonal dependence of geomagnetic activity, taking into account orientation of large-scale plasma structures (of the magnetic cloud type) of the solar wind. The contribution of magnetic clouds of different orientation in the periods of equinoxes and solstices is demonstrated. It is established that in equinox periods the geomagnetic activity increases due to ejections with small angles of inclination of their axis to the ecliptic plane, most frequently detected in near-Earth space. In solstice periods, such clouds are not geoeffective structures because of a decreased magnitude of projection of the magnetic field of cloud axis onto the Earth’s magnetic dipole during such intervals. This effect reveals itself in a reduced level of geomagnetic activity in summer and winter.

Modeling of Separation of Granular Materials on Multiple-Deck Classifiers Using the Theory of Stochastic Processes

Abstract: The mathematical model of the separation of granular materials on multiple-deck sieve classifiers has been constructed using the theory of Poisson processes and the model has been identified. The problem of the optimal implementation of the process in multicriterial setting has been formulated and solved; the engineering simulation of the classifier has been performed using this solution.

Some problems of multicriteria process optimization

Abstract: A brief review of general approaches to solving multicriteria optimization problems, their advantages and disadvantages, and computational bottlenecks in the solution of certain problems with numerical implementation was performed. The optimization solutions for three specific types of engineering processes were given with relation to the construction of their mathematical models based on different approaches. The numerical results of solving the optimization problems for the considered examples used in practice for the optimal implementation of corresponding processes were obtained.